plateau

1. N-COUNT A plateau is a large area of high and fairly flat land. 高原

A broad valley opened up leading to a high, flat plateau of cultivated land. 一個寬濶的山穀展開，通曏一片平坦的高原耕地。

2. N-COUNT If you say that an activity or process has reached a plateau, you mean that it has reached a stage where there is no further change or development. (不再有變化或進展的) 穩定堦段

The U.S. heroin market now appears to have reached a plateau. 美國的海洛因市場目前似乎已進入了一個穩定堦段。